Canada is a big player in official treaty co-productions. Co-pros work for Canadian producers because their home market is small, so they need to collaborate with international partners to develop, finance and produce product that can be sold internationally. But co-productions take great care to structure, and partners must ensure a balance of their diverse interests.

In addition, there can be restrictions on choices of cast, creative and technical talent.

That said, the positives make co-pros worth pursuing, since they open new markets for Canadian producers and enable foreign producers to acquire a "North American" sensibility for their projects by partnering with a Canadian producer.

Recent bilateral or multipartite co-productions include Fernando Meirelles' Cannes opener "Blindness," a Brazil-Canada-Japan co-production that involved a Canadian screenwriter, was based on Portuguese author Jose Saramago's Nobel Prize-winning novel, featured U.S. stars like Julianne Moore and Mark Ruffalo, and secured $15 million, or half of its budget, from Japan.

Another example is Showtime's "The Tudors," structured as a Canada-Ireland co-production between Peace Arch Entertainment and Reveille Prods. to tap government subsidies, and shot in Ireland and posted in Canada.

"It's a win-win for everyone," says David Zitzerman, an entertainment lawyer with Toronto-based Goodmans. "The producers get financing from Ireland and Canada to cut their production costs, and Showtime gets to pay less money because other people pay more."